Experimental and theoretical studies of a thermal switch based on shape-memory alloy cladded with graphene paper

ABSTRACT

Thermal switches control thermal circuits and are widely used in electronics and engineering. Shape-memory alloys can be deformed by heating, which is widely used as a driving part for thermal switches by many research groups. Shape-memory alloys are inappropriately used in thermal switches as the heat transfer components because of their lower thermal conductivity. Components responsible for the heat transfer and driving are usually separated from each other inside the device. Such design increases the complexity of the device and its production cost. By combining high thermal conductivity and self-driving properties of the shape-memory alloys, the structure of the thermal switch can significantly not only simplify its design but also can improve its performance. In this paper, we implemented two-way memory alloy as the drive device. Graphene paper was used to cover the surface of the memory alloy. Self-actuation of the shape-memory alloy and high thermal conductivity of graphene enhance heat conduction of the switch. The resulting device has a simple structure, is flexible, stable and easy to operate. We thoroughly studied structure and working principle of this thermal switch. Both simulations and experimental tests were performed to analyze thermal conductivity of the switch. We obtained a switch ratio equal to 54.0 ± 24.3. Our thermal switch is very promising for the advanced thermal management of the electronic devices.

KEYWORDS:

• Thermal switch
• shape-memory alloy
• graphene
• heat conduction
• simulation

Acknowledgements

This work was supported by the Natural Science Foundation of China (Grant No. 51372042, 51872053), Guangdong Provincial Natural Science Foundation (2015A030308004), and the NSFC-Guangdong Joint Fund (Grant No. U1501246).